Dirty rock has fines that can cause system malfunction by reducing the long-term acceptance rate of the underlying soil or media. Unwashed rock may be able to meet these specifications, but most rock needs to be washed to remove fine soil components.
Washed rock is used as distribution media in soil treatment area, media filters and in interceptor drains. It is obtained from quarries and gravel pits and is produced by screening, grading and washing to meet the desired specifications.
In general, rock should be clean, sound...
